Pavement surfaces, such as asphalt and concrete, are used to carry traffic, including vehicles (e.g., automobiles, bikes, construction equipment) and humans. Pavement surfaces may need additional friction on portions thereof (e.g., sections with cornering, sections where braking is required) to increase the safety of the traffic traveling thereon. The additional friction is known as high friction surfacing. The high friction surfacing may be provided by placing an adhesive material on the underlying pavement surface (substrate) and then securing aggregate to the adhesive. The adhesive layer is typically a wet polymer layer, such as epoxy, polyurethane, or bitumen. The adhesive layer is applied (overlaid) on the substrate and then aggregate is applied onto the adhesive layer prior to the adhesive layer curing.
The materials typically used as the adhesive layer undergo changes in their properties when there are changes in temperature. Bitumen and the substrate layer (concrete or asphalt) are thermally compatible, meaning that their dimensional properties change at the same rate with changing temperatures. However, epoxy/polyurethane and the substrate layer are thermally incompatible, meaning that their dimensional properties change at different rates. The thermal incompatibility may result in delamination of the epoxy/polyurethane from the pavement surface or damage to the pavement surface.
In addition, the adhesive materials undergo changes in their properties as the materials age. For example, epoxies/polyurethanes will experience steric hardening as does asphalt. Bitumens will age harden through loss of volatiles. Furthermore, the adhesive layers may break down over time due to, for example, continued exposure to UV light.
The existing adhesive materials utilized for high friction surfacings (e.g., bitumen, epoxies, polyurethanes) are installed full width and rely totally on the size and nature of the aggregate to provide the macro and microtexture to provide friction. These surfaces are therefore highly susceptible to rainfall intensity.